Fix conversions from &_ to Val (#1502)

### What
  Add support for conversions from &Vec<T>, &Map<>, String, etc to Val.

  ### Why
All SDK types should be convertible to `Val` either from an owned value,
e.g. `Vec<T>`, or from a borrowed value, e.g. `&Vec<T>`.

Close #1500

Author: leighmcculloch

soroban-sdk-macros/src/derive_enum.rs

@@ -192,6 +192,14 @@ pub fn derive_type_enum(
                 }
             }
         }
+
+        impl #path::TryFromVal<#path::Env, &#enum_ident> for #path::Val {
+            type Error = #path::ConversionError;
+            #[inline(always)]
+            fn try_from_val(env: &#path::Env, val: &&#enum_ident) -> Result<Self, #path::ConversionError> {
+                <_ as #path::TryFromVal<#path::Env, #enum_ident>>::try_from_val(env, *val)
+            }
+        }
     };
 
     // Additional output when testutils are enabled.

soroban-sdk-macros/src/derive_enum_int.rs

@@ -117,6 +117,14 @@ pub fn derive_type_enum_int(
                 })
             }
         }
+
+        impl #path::TryFromVal<#path::Env, &#enum_ident> for #path::Val {
+            type Error = #path::ConversionError;
+            #[inline(always)]
+            fn try_from_val(env: &#path::Env, val: &&#enum_ident) -> Result<Self, #path::ConversionError> {
+                <_ as #path::TryFromVal<#path::Env, #enum_ident>>::try_from_val(env, *val)
+            }
+        }
     };
 
     // Additional output when testutils are enabled.

soroban-sdk-macros/src/derive_error_enum_int.rs

@@ -188,5 +188,13 @@ pub fn derive_type_error_enum_int(
                 Ok(error.into())
             }
         }
+
+        impl #path::TryFromVal<#path::Env, &#enum_ident> for #path::Val {
+            type Error = #path::ConversionError;
+            #[inline(always)]
+            fn try_from_val(env: &#path::Env, val: &&#enum_ident) -> Result<Self, #path::ConversionError> {
+                <_ as #path::TryFromVal<#path::Env, #enum_ident>>::try_from_val(env, *val)
+            }
+        }
     }
 }

soroban-sdk-macros/src/derive_struct.rs

@@ -129,6 +129,14 @@ pub fn derive_type_struct(
                 Ok(env.map_new_from_slices(&KEYS, &vals).map_err(|_| ConversionError)?.into())
             }
         }
+
+        impl #path::TryFromVal<#path::Env, &#ident> for #path::Val {
+            type Error = #path::ConversionError;
+            #[inline(always)]
+            fn try_from_val(env: &#path::Env, val: &&#ident) -> Result<Self, #path::ConversionError> {
+                <_ as #path::TryFromVal<#path::Env, #ident>>::try_from_val(env, *val)
+            }
+        }
     };
 
     // Additional output when testutils are enabled.

soroban-sdk-macros/src/derive_struct_tuple.rs

@@ -118,6 +118,14 @@ pub fn derive_type_struct_tuple(
                 Ok(env.vec_new_from_slice(&vals).map_err(|_| ConversionError)?.into())
             }
         }
+
+        impl #path::TryFromVal<#path::Env, &#ident> for #path::Val {
+            type Error = #path::ConversionError;
+            #[inline(always)]
+            fn try_from_val(env: &#path::Env, val: &&#ident) -> Result<Self, #path::ConversionError> {
+                <_ as #path::TryFromVal<#path::Env, #ident>>::try_from_val(env, *val)
+            }
+        }
     };
 
     // Additional output when testutils are enabled.

soroban-sdk/src/bytes.rs

@@ -160,6 +160,14 @@ macro_rules! impl_bytesn_repr {
             }
         }
 
+        impl TryFromVal<Env, &$elem> for Val {
+            type Error = ConversionError;
+
+            fn try_from_val(_env: &Env, elt: &&$elem) -> Result<Self, Self::Error> {
+                Ok(elt.to_val())
+            }
+        }
+
         #[cfg(not(target_family = "wasm"))]
         impl From<&$elem> for ScVal {
             fn from(v: &$elem) -> Self {

soroban-sdk/src/crypto/bls12_381.rs

@@ -505,6 +505,14 @@ impl TryFromVal<Env, Fr> for Val {
     }
 }
 
+impl TryFromVal<Env, &Fr> for Val {
+    type Error = ConversionError;
+
+    fn try_from_val(_env: &Env, fr: &&Fr) -> Result<Self, Self::Error> {
+        Ok(fr.to_val())
+    }
+}
+
 #[cfg(not(target_family = "wasm"))]
 impl From<&Fr> for ScVal {
     fn from(v: &Fr) -> Self {
@@ -761,3 +769,74 @@ impl Bls12_381 {
         U256::try_from_val(env, &v).unwrap_infallible().into()
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_g1affine_to_val() {
+        let env = Env::default();
+
+        let g1 = G1Affine::from_bytes(BytesN::from_array(&env, &[1; 96]));
+        let val: Val = g1.clone().into_val(&env);
+        let rt: G1Affine = val.into_val(&env);
+
+        assert_eq!(g1, rt);
+    }
+
+    #[test]
+    fn test_ref_g1affine_to_val() {
+        let env = Env::default();
+
+        let g1 = G1Affine::from_bytes(BytesN::from_array(&env, &[1; 96]));
+        let val: Val = (&g1).into_val(&env);
+        let rt: G1Affine = val.into_val(&env);
+
+        assert_eq!(g1, rt);
+    }
+
+    #[test]
+    fn test_doule_ref_g1affine_to_val() {
+        let env = Env::default();
+
+        let g1 = G1Affine::from_bytes(BytesN::from_array(&env, &[1; 96]));
+        let val: Val = (&&g1).into_val(&env);
+        let rt: G1Affine = val.into_val(&env);
+
+        assert_eq!(g1, rt);
+    }
+
+    #[test]
+    fn test_fr_to_val() {
+        let env = Env::default();
+
+        let fr = Fr::from_bytes(BytesN::from_array(&env, &[1; 32]));
+        let val: Val = fr.clone().into_val(&env);
+        let rt: Fr = val.into_val(&env);
+
+        assert_eq!(fr, rt);
+    }
+
+    #[test]
+    fn test_ref_fr_to_val() {
+        let env = Env::default();
+
+        let fr = Fr::from_bytes(BytesN::from_array(&env, &[1; 32]));
+        let val: Val = (&fr).into_val(&env);
+        let rt: Fr = val.into_val(&env);
+
+        assert_eq!(fr, rt);
+    }
+
+    #[test]
+    fn test_double_ref_fr_to_val() {
+        let env = Env::default();
+
+        let fr = Fr::from_bytes(BytesN::from_array(&env, &[1; 32]));
+        let val: Val = (&&fr).into_val(&env);
+        let rt: Fr = val.into_val(&env);
+
+        assert_eq!(fr, rt);
+    }
+}

soroban-sdk/src/map.rs

@@ -216,6 +216,18 @@ where
     }
 }
 
+impl<K, V> TryFromVal<Env, &Map<K, V>> for Val
+where
+    K: IntoVal<Env, Val> + TryFromVal<Env, Val>,
+    V: IntoVal<Env, Val> + TryFromVal<Env, Val>,
+{
+    type Error = Infallible;
+
+    fn try_from_val(_env: &Env, v: &&Map<K, V>) -> Result<Self, Self::Error> {
+        Ok(v.to_val())
+    }
+}
+
 impl<K, V> From<Map<K, V>> for Val
 where
     K: IntoVal<Env, Val> + TryFromVal<Env, Val>,
@@ -657,6 +669,39 @@ mod test {
         assert_eq!(map.len(), 0);
     }
 
+    #[test]
+    fn test_map_to_val() {
+        let env = Env::default();
+
+        let map = Map::<u32, ()>::from_array(&env, [(0, ()), (1, ()), (2, ()), (3, ())]);
+        let val: Val = map.clone().into_val(&env);
+        let rt: Map<u32, ()> = val.into_val(&env);
+
+        assert_eq!(map, rt);
+    }
+
+    #[test]
+    fn test_ref_map_to_val() {
+        let env = Env::default();
+
+        let map = Map::<u32, ()>::from_array(&env, [(0, ()), (1, ()), (2, ()), (3, ())]);
+        let val: Val = (&map).into_val(&env);
+        let rt: Map<u32, ()> = val.into_val(&env);
+
+        assert_eq!(map, rt);
+    }
+
+    #[test]
+    fn test_double_ref_map_to_val() {
+        let env = Env::default();
+
+        let map = Map::<u32, ()>::from_array(&env, [(0, ()), (1, ()), (2, ()), (3, ())]);
+        let val: Val = (&&map).into_val(&env);
+        let rt: Map<u32, ()> = val.into_val(&env);
+
+        assert_eq!(map, rt);
+    }
+
     #[test]
     fn test_raw_vals() {
         let env = Env::default();

soroban-sdk/src/string.rs

@@ -111,6 +111,14 @@ impl TryFromVal<Env, String> for Val {
     }
 }
 
+impl TryFromVal<Env, &String> for Val {
+    type Error = ConversionError;
+
+    fn try_from_val(_env: &Env, v: &&String) -> Result<Self, Self::Error> {
+        Ok(v.to_val())
+    }
+}
+
 impl From<String> for Val {
     #[inline(always)]
     fn from(v: String) -> Self {
@@ -269,6 +277,7 @@ impl String {
 #[cfg(test)]
 mod test {
     use super::*;
+    use crate::IntoVal;
 
     #[test]
     fn string_from_and_to_slices() {
@@ -311,4 +320,37 @@ mod test {
         let mut out = [0u8; 10];
         s.copy_into_slice(&mut out);
     }
+
+    #[test]
+    fn string_to_val() {
+        let env = Env::default();
+
+        let s = String::from_str(&env, "abcdef");
+        let val: Val = s.clone().into_val(&env);
+        let rt: String = val.into_val(&env);
+
+        assert_eq!(s, rt);
+    }
+
+    #[test]
+    fn ref_string_to_val() {
+        let env = Env::default();
+
+        let s = String::from_str(&env, "abcdef");
+        let val: Val = (&s).into_val(&env);
+        let rt: String = val.into_val(&env);
+
+        assert_eq!(s, rt);
+    }
+
+    #[test]
+    fn double_ref_string_to_val() {
+        let env = Env::default();
+
+        let s = String::from_str(&env, "abcdef");
+        let val: Val = (&&s).into_val(&env);
+        let rt: String = val.into_val(&env);
+
+        assert_eq!(s, rt);
+    }
 }

soroban-sdk/src/tests.rs

@@ -21,6 +21,7 @@ mod contract_store;
 mod contract_timepoint;
 mod contract_udt_enum;
 mod contract_udt_enum_error;
+mod contract_udt_enum_int;
 mod contract_udt_enum_option;
 mod contract_udt_option;
 mod contract_udt_struct;